Surface amplification of pencil graphite electrode using CuO nanoparticle/polypyrrole nanocomposite; a powerful electrochemical strategy for determination of tramadol

An amplified tramadol electrochemical sensor was fabricated based on surface modification of pencil graphite electrode (PGE) by CuO nanoparticle (CuO-NPs) and polypyrrole (pPy). The PGE/CuO-NPs/pPy showed excellent electro-catalytic activity for oxidation determination of tramadol with improving oxidation current about 4.55 times. Using square wave voltammetric investigation, the over-potential oxidation of tramadol was decreased about 40 mV compare to oxidation potential of drug at unmodified PGE. The result showed that the electro-oxidation of tramadol at the surface of PGE/CuO-NPs/pPy and in the aqueous solution has a dependent pH behavior with an equal exchange of electron and proton. In the analytical investigation using the square wave voltammetric method, the PGE/CuO-NPs/pPy showed more advantage for the determination of tramadol in the concentration range 5.0 mu M-380 mu M with detection limit 1.0 nM. In addition, the PGE/CuO-NPs/pPy showed acceptable data for the determination of tramadol in drug samples.